Disposable electrode assembly



June 1951 c. w. J. HEDBERG DISPOSABLE ELECTRODE ASSEMBLY 2 Sheets-Sheet1 Filed Aug. 2'7, 1946 Q hm 3 mm Qw INVENTOR. Carl W Jjiedbery.

June 5, 1951 w, J HEDBERG 2,555,339

DISPOSABLE ELECTRODE ASSEMBLY Filed Aug. 27, 1946 2 Sheets-Sheet 2 IN VEN TOR.

Carl W JHedberg.

BY v

LSMy-M Patented June 5, 1951 DISPOSABLE ELECTRODE ASSEMBLY Carl W. J.Hedberg, Bound Brook, N. J., assignor to Research Corporation, New York,N. Y., a corporation of New York Application August 27, 1946, Serial No.693,247

This invention relates to electrical precipitators and more particularlyto electrical precipitators having disposable extended surfaceelectrodes.

Objects of the invention are to provide in an electrical precipitatordisposable extended surface electrodes which may be readily removed anddiscarded after they have become coated with precipitated matter andwhich may be replaced by fresh electrodes; to provide relativelyinexpensive electrode structures which are economical to discard whenthey have become damaged or dirty; to provide disposable electrodes madefrom water-laid or other fibrous material such as cardboard or a morebibulous paper, papier mache, textile fabric impregnated with astiffening agent; and the like. Other objects are to provide anelectrical precipitator having disposable extended surface electrodes ofthe character described, the electrodes having either smooth orroughened particle-collecting surfaces and which may be madeadditionally conducting for precipitation purposes by impregnating theelectrode structures with suitable wetting liquids, or incorporatingconductive substances in the material from which the electrodes areformed, or by coating one or more surfaces of the electrodes with aconducting film or network.

Typically, the invention may be embodied in an electrical precipitatorcomprising extended surface electrode support means, insulating meanssupporting high tension electrodes in complementary relation to theextended surface electrode support means, and extended surface electrodestructures carried by the first-mentioned support means in spacedrelation to the high tension electrodes, the extended surface electrodestructures being removable independently of the high tension electrodes.The removable electrode structures may be formed from a variety ofmaterials, principally fibrous materials, as will be explained ingreater detail hereinafter, and these structures may have roughenedcollecting surfaces and/or may be made additionally conductive in waysto be more fully developed.

The invention will be described with greater particularity, and other ofits aims and advantages will be in part apparent and in part pointed outin the following detailed description, reference being had to theaccompanying drawing, in which:

Fig. l is a vertical sectional view of an electrical precipitatorembodying the invention, taken along a plane parallel to the directionof gas flow through the precipitator;

10 Claims. (Cl. 1837) Fig. 2 is an end view of the precipitator shown inFig. 1;

Fig. 3 is a perspective view of an extended surface electrode supportforming a part of the precipitator illustrated in Figs. 1 and 2;

Fig. 4 is an end View of a disposable cellular extended surfaceelectrode;

Fig. 5 is a plan view of a partition element of the electrode shown inFig. 4 and Fig. 6 is a fragmentary sectional View of a modified form ofa cellular extended surface electrode.

Referring to the drawings, particularly to Figs. 1 and 2 thereof, theelectrical precipitator shown is of the two-stage type and includes acharging stage or section [0, a collection stage or section II and anintermediate high tension compartment I2. The precipitator is providedwith a casing [3 open at the ends to permit a stream of gas bearingsuspended particulate matter to be passed through the casing from leftto right, as indicated by the arrow in Fig. 1.

In the charging and collection zones there are positioned identicalsupports l4, one of which is shown in perspective in Fig. 3. A support[4 may take the form of an open framework, preferably constructed fromsteel channel stock and flat stock welded together. It provides aplurality of contiguous compartments l5 for the reception of disposableextended surface electrode structures 16, the latter being shown indetail in Fig. 4.

Referring to Fig. 4, the extended surface electrode structure l6 has ahollow rectangular outer shell I! and a plurality of interlockingpartition elements l8 dividing the interior of the shell into aplurality of longitudinal cells. Both the shell and partitions may beformed from cardboard or other similar stock.

One of the partition elements is shown in plan view in Fig. 5; it isprovided with a pair of parallel cuts or slots l9 extendinglongitudinally for onehalf the length of the partition and dividing thepartition laterally into three sections of approximately equal size andshape. The partition also has tabs or ears 20 projecting from itslongitudinal sides. Four such partitions are interlocked in the mannerof an egg crate separator and are inserted in the outer shell H, theears 20 projecting through corresponding short slots formed in the sidesof the outer shell, as shown in Fig. 4. The assembled extended surfaceelectrode structure may then be' inserted as a unit in one of thecompartments l5 of the electrode support.

It will be apparent that the electrode structure I6 is convenient toship and easy to assemble. The assembled unit may be collapsed forshipment by merely pressing two of its diagonally opposite longitudinaledges towards each other, or it may be shipped erect in the form shownin Fig. 4. Alternatively, if desired, the assembly may be shippedknocked-down the outer shell being collapsed to occupy a minimum ofspace.

In addition to providing support for the extended surface electrodestructures, the support l4 also carries a high tension electrodeassembly. The high tension electrode assembly}! for the charging stagediffers functionally and in minor but important structural respects'frpmtlie high tension electrode assembly 22 for the collection stage,but the two assemblies are mounted upon their respective supports M insubstantially the same Way. H

The high tension electrode assembly for the charging stage includesalattice 23, preferably of welded 'fntall'ic construction, the crossedmembers of the lattice being spaced on centers corresponding to'thelcent'e'r's'of the individual extended surface electrode cells. Thelattice is mountedon ihsulators 24 carried by the support l4.

The charging electrodes '25 are supported by I the lattice 23 incantilever fashion. The butts of the electrodes are received in holesformed at the juncturesofthe lattic'e'elments and are secured therein asby welding. On'e charging electrode 25 i s provided for each cell of theextended surfacade-circu structure. The main body of the electrode 25may be in the form of a metallic rod log "a substantial radius ofcurvature not pted to provide corona discharge, while the up, .26 of theelectrode is formed of a short length of fine wire welded to the rod toprovide a sec'tidn raving very'small radius of curvature adapted to'provide corona or brush discharge.

The precipitating'electrode assembly 22 for the collection stage, asstated ls generally similar in 'e t'ructi'on to the'elect'rode'fas'semblyil, and is s larly mounted. The electrode elements21 differ froin the corresponding elements 25 primariry that they 'fdonot have a fine-wire tip hence provide only a high tension electricfieldwithou't corona discharge.

A diagrammatic showing of the power supply appears 'inFi g. 1. Thecasing |'3 maybe groundea as at "28 and high Voltage current conductors29 and 38 may be connected to a source or sources offcurreht (not shown)"for supplying current to the high tension electrode assemblies 2| and22, respectiyely.

The extended "surface electrode structure shown in detail in Fig.4 isconstructed from plane-surfaced cardboard. A modified form, a fragmentof which is shown 'in'Fig. 6, is made of corrugated paperboard, thecorrugations 3| of which extend transversely of the cell in a directionat right angles to the direction of flow of the gas stream.therethrjough. [These corrugations provide a series of pockets in theextended surface electrode inwhichprecipitated material will adherevwith greater tenacity than to a plane surface. There is thus lesslikelihood of the precipitate'd material. ,being strippedfrom thesurface of the electrode and becoming re-entrained in .the gas stream.Of coursathe surface of the extendedsurface electrodes may be roughenedin o h r pa t f d ir Aswillbeunderstood by persons skilled in theart,..th,e, curr6 2.fiOW in the space between the complementaryelectrodes of electrical precipithe disposable electrode may beincreased by wetting the material with a conductive liquid. such liquidpreferably is also somewhat viscous or adhesive, which propertyincreases the stickiness of the surface of the disposable electrodewhereby more effectively to hold precipitated matter. I have found thatliquids such as aqueous solutions of calcium chloride, lithium chlorideginc chloride, and other hygroscopic salts are well-suited for thispurpose. Triethylene glycol, with or without a wetting agent, can beusedto advantage.

The conductivity of the material of the disposable electrodes can alsobe increased by incorporating conductive material such as metallicfibers or carbon powder, including graphite, in the fibrous. sheet.structure. Alternatively, the sheets maybe coated with a conductivelayer or film of carbon, graphite, or metal powder. Also, the sheetmaterial forming the extended surface electrodes may be paper orcardboard having an adherent surface layer consisting of thin metallicfoil.

The operation of the electrical precipitator herein shown and describedis believed to be obvious from the foregoing description. In brief,however, a high tension electric field accompanied by brush discharge iscreated between 'the complementary electrodes of the charging stage I0by impressing on the electrodes, through conductors 28 and '29, a highelectrical potential. A similar field, but without brush discharge, iscreated between'thec'omplementary electrodes of the collection stage I].'A stream of gas bearing suspended particles is passed through theprecipitato'r in the direction of the arrow of Fig. 1. In the chargingstage, the suspended particles are given an electric charge as willb'eunderstood by those skilled in the art to which this invention pertains.Some of the charged particles are attracted to the surfaces of theextended surface electrodes in the charging stage and are depositedthereon. In the collection stage, most of the residual charged suspendedmatter is precipitated upon the walls 'of the disposable electrodestructures. It will be understood that electrical connectionisestablished between the disposable electrode structures and theirsupporting frames '[4 by direct contact between these 'elernents, butsuch connection maybe made,if desired, by metallic conductors which maybe soldered to the supports l4 and clipped or otherwise attached to theelectrode structure.

When the disposable electrodes have become so coated with precipitatedmaterial that ciliciency of precipitation is impaired and danger ofdisruptive dischargeis imminent, the precipitatormay be shut down, thedisposable electrode structures removed by Simplypulling them out oftheir compartments in the support frames, new electrode structuresinserted, and the precipitator once more putinto operation, all in avery short time and with a minimum of inconvenience and expense. p

It will be obvious that the extended surface collecting electrodestructures may take the form not only of a plurality of interlockingsheets of. fibrous material defining a plurality of parallel conduits,but also may take the form of a plurality of sheets of fibrous material,however arranged, cooperating to define a plurality of parallelconduits.

' From the foregoing description, it will be seen that the presentinvention provides disposable electrode structures for electricalprecipitators which greatly facilitate the construction, arrangement andoperation of such precipitators. It will also be apparent that theinvention permits of a variety of modifications not specifically shownand described without departing from the spirit and scope of theinvention as defined in the claims.

I claim:

1. In an electrical precipitator, extended surface electrode supportmeans defining a longitudinally extending precipitation zone having anopening into each end thereof, an extended surface electrode structurecarried by said support means comprising a plurality of water-laidfibrous sheet members constructed and arranged to define a plurality oflongitudinally extending conduits in said precipitation zone, saidextended surface structure being positionable into and removable fromsaid support means through the opening at one end thereof, high tensionelectrode mounting means adjacent the other end of said support means,and substantially rigid high tension electrodes mounted in said mountingmeans to project into said conduits through the opening in said otherend of the support means.

2. In an electrical precipitator, extended surface electrode supportmeans defining a longitudinally extending precipitation zone having anopening into each end thereof, an extended surface electrode structurecarried by said support means comprising a plurality of interlockingwater-laid fibrous sheet members constructed and arranged to define aplurality of longitudinally extending conduits in said precipitationzone, said extended surface structure being positionable into andremovable from said support means through the opening at one endthereof, high tension electrode mounting means adjacent the other end ofsaid support means, and substantially rigid high tension electrodesmounted in said mounting means to project into said 0011- duits throughthe opening in said other end of the support means.

3. In an electrical precipitator, extended surface electrode supportmeans defining a longitudinally extending precipitation zone having anopening into each end thereof, an extended surface electrode structurecarried by said support means comprising a plurality of water-laidfibrous sheet members including a conduction increasing substanceconstructed and arranged to define a plurality of longitudinallyextending conduits in said precipitation zone, said extended surfacestructure being positionable into and re movable from said support meansthrough the opening at one end thereof, high tension electrode mountingmeans adjacent the other end of said support means, and substantiallyrigid high tension electrodes mounted in said mounting means to projectinto said conduits through the opening in said other end of the supportmeans.

4. In an electrical precipitator, extended surface electrode supportmeans defining a longitudinally extending precipitation zone having anopening into each end thereof, an extended surface electrode structurecarried by said support means comprising a plurality of Water-laidfibrous sheet members including a conductive liquid constructed andarranged to define a plurality of longitudinally extending conduits insaid precipitation zone, said extended surface structure beingpositionable into and removable from said support means throughtheopening at one end thereof, high tension electrode mounting meansadjacent the other end of said support means, and substantially rigidhigh tension electrodes mounted in said mounting means to project intosaid conduits through the opening in said other end of the supportmeans.

5. In an electrical precipitator, extended surface electrode supportmeans defining a longitudinally extending precipitation zone having anopening into each end thereof, an extended surface electrode structurecarried by said support means comprising a plurality of water-laidfibrous sheet members including a comminuted solid conducting substanceconstructed and arranged to define a plurality of longitudinallyextending conduits in said precipitation zone, said extended surfacestructure being positionable into and removable from said support meansthrough the opening at one end thereof, high tension electrode mountingmeans adjacent the other end of said support means, and substantiallyrigid high tension electrodes mounted in said mounting means to projectinto said conduits through the opening in said other end of the supportmeans.

6. In an electrical precipitator, extended surface electrode supportmeans defining a longitudinally extending precipitation zone having anopening into each end thereof, an extended surface electrode structurecarried by said support means comprising a plurality of corrugated paperboard sheet members constructed and arranged to define a plurality oflongitudinally extending conduits in said precipitation zone, saidextended surface structure being positionable into and removable fromsaid support means through the opening at one end thereof, high tensionelectrode mounting means adjacent the other end of said support means,and substantially rigid high tension electrodes mounted in said mountingmeans to project into said conduits through the opening in said otherend of the support means.

7. An extended surface electrode structure for electrical precipitatorscomprising an elongate tubular member, a plurality of substantiallyparallel partition members in said tubular member extendinglongitudinally of and spaced laterally of said tubular member, saidpartition members extending between and being supported by opposed wallsof said tubular member, additional substantially parallel partitionmembers in said tubular member extending longitudinally of and spacedlaterally of said tubular member and intersecting at least some of saidfirst mentioned partition members, said additional partition membersextending between and being supported by opposed walls of said tubularmember, said partition members having cooperating interlocking slotsalong their lines of intersection.

8. An extended surface electrode structure as defined in claim 7 whereinsaid tubular member and said partition members comprise water-laidfibrous material.

9. An extended surface electrode structure as defined in claim 7 whereinsaid tubular member and said partition members comprise corrugated 15paper board.

7 10. An eiitended "surfaee "electrode structure-as defined in'claim 7wherein said tubular member and said partition members comprisewater-laid fibrous material including a "conduction increasingsubstance.

CARL W. J. HEDBERG. REFERENCES oI'r En h The following references are ofrecord in the file of this patent: 7

UNITED STATES PATENTS Name Date Schmidt May 11, 1920 Number Number NameDate Weiskoff Sept. 21, 1926 Anderson Feb. 19, 1935 Brion et a1. July 6,1937 FOREIGN PATENT$ Country v Date Germany May 2, 1918 Germany Sept.29, 1922 Germany May 27, 1927 Germany Jan. 27, 1930

